Enatsu Hiroshi

Hiroshi Enatsu (12 September 1922 – 4 August 2019) was a Japanese theoretical physicist who contributed to a relativistic Hamiltonian formalism in quantum field theory.

Academic works Enatsu has found that the commutation relation

in a relativistic Hamiltonian formalism is equivalent to that in the conventional non-relativistic Hamiltonian formalism of quantum field theory, where is the commutator, is space-time coordinates, is proper time, is Hermitian adjoint of , and is the Dirac delta function, with the aid of the relation

.

Here, a step function follows for , and for .

Biography Early stage Enatsu was born on 12 September 1922 in Miyakonojō as a son of Eizo and Fumi (Kuroiwa) Enatsu. Miyakonojō is a town within the territory of the former Satsuma Domain, and it was rather natural for Enatsu to receive an education in Kagoshima. So, he spent in Kagoshima for secondary education and junior college.

Encounter with Hideki Yukawa In the last year of junior college, Hideki Yukawa made a lecture on meson theory at Kagoshima. After listening to the lecture, Enatsu became interested in Yukawa and meson theory, so he decided to study under Yukawa. He studied on meson theory under Yukawa in undergraduate course. He received Bachelor of Science from Kyoto Imperial University in 1944. He received Doctor of Science. from Kyoto Imperial University in 1953 under Yukawa. Enatsu was an assistant under Yukawa at Kyoto University from 1946 to 1957. Enatsu was a research assistant at Columbia University in New York City from 1952 to 1953.

Encounter with Niels Bohr Enatsu was a visiting member of the Institute for Theoretical Physics in Copenhagen from 1955 to 1956. During his stay in Copenhagen, he could ask some questions to Bohr almost every week. It was a special treatment.

Professor at Ritsumeikan University In 1957, Enatsu was an assistant professor and inaugurated a professor at Ritsumeikan University in Kyoto. From 1971 to 1972, he was also the dean of faculty of science and engineering at Ritsumeikan University. In 1988, he retired from a professor at Ritsumeikan University in Kyoto, and has been a professor emeritus. In 1997. he received the 3rd class of the Order of the Sacred Treasure. Enatsu died on 4 August 2019 in Kyoto